Speech recognition technology is a technology that enables a machine to convert a speech signal into a corresponding text or command by means of recognition and understanding. For example, after receiving the user's speech instruction, a mobile phone that possesses speech recognition function performs analog to digital conversion of the speech instruction to obtain a corresponding digital signal, and further recognizes the content of the speech instruction based on the converted digital signal. For instance, the content of the speech instruction is “unlock”, so the mobile phone generates control signalling for unlocking based on the content of the speech instruction so as to perform unlocking operation of the mobile phone.
However, during the above speech recognition process, only the content of the received speech instruction can be recognized while the subject issuing the speech instruction cannot be determined, which would decrease the accuracy of speech recognition and even lead to unnecessary risks of misoperation. For example, any user can unlock the mobile phone by applying a speech signal of “unlock” instruction, causing hidden trouble in security of the user's information.